Biology · General Awareness

Muscle Biology

836 Questions

Muscle biology covers the structures, functions, and contraction mechanisms of skeletal, cardiac, and smooth muscles. Test questions target filaments, stimuli, and specific muscle roles. A clear understanding helps secure marks in biology sections.

Skeletal muscle controlCardiac muscle propertiesMuscle contraction mechanismActin and myosin filamentsMuscle functions

Muscle Biology Questions

Multiple choice zoology locomotion and reproduction flagella other cell components single membrane bound organelles

Which of the cilia protein is analogous to myosin of muscles?

  1. Tubulin

  2. Dynein

  3. Flagellin

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Dynein forms an integral part of cilia. It is a motor protein which converts the chemical energy contained in ATP into the mechanical energy of movement. Dynein transports various cellular cargo by "walking" along cytoskeletal microtubules towards the minus-end of the microtubule, which is usually oriented towards the cell center. 

Axonemal dynein causes sliding of microtubules in the axonemes of cilia and flagella and is found only in cells that have those structures. There are parallels between the sliding filaments of skeletal muscle myosin and the sliding microtubules of cilia. Both are powered by ATP. Both motors dynein in cilia, myosin in skeletal muscle are ATPases. Both are regulated by calcium ions. 

Multiple choice evs our body- its internal organ system leucocytes body fluids and immune responses respiratory and circulatory system

Myoglobin is found in

  1. White fibres

  2. Red fibres

  3. Can be traced in both

  4. Cardiac muscles only
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Myoglobin is found in red fibres.

Myoglobin contains a heme (prosthetic) group which is responsible for its main function (carrying of oxygen molecules to muscle tissues). Myoglobin can exist in the oxygen free form, deoxymyoglobin, or in a form in which the oxygen molecule is bound, called oxymyoglobin.
Myoglobin is an iron and oxygen-binding protein found in the muscle tissue of vertebrates in general and in almost all mammals. It is related to hemoglobin, which is the iron and oxygen-binding protein in blood, specifically in the red blood cells. In humans, myoglobin is only found in the bloodstream after muscle injury
So, the correct answer is 'Red fibres'

Multiple choice zoology locomotion and movement contractile protein structure of muscle muscles and their structure

The important muscle proteins that helps in the movement are 

  1. Actin and myosin

  2. Troponin

  3. Tropomyosin

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • Skeletal muscle fiber is made up of two types of filaments. They are thick filament (myosin) and thin filament (actin). Contraction of a muscle fiber takes place by the sliding of the thin filaments over the thick filaments.
  • Myosin (thick) filament is also a polymerized protein. Many monomeric proteins called meromyosins constitute one thick filament. 
  • Each actin (thin) filament is made of two ‘F’ (filamentous) actins helically wound to each other. Each ‘F’ actin is a polymer of monomeric ‘G’ (Globular) actins. Two filaments of another protein, tropomyosin also run close to the ‘F’ actins throughout its length. A complex protein troponin is distributed at regular intervals on the tropomyosin.
  • Hence, the important muscles proteins that help in the movement are actin and myosin, troponin and tropomyosin.
  • So, the correct answer is 'All of the above'.
Multiple choice zoology locomotion and movement contractile protein structure of muscle muscles and their structure

In resting stage, binding sites for myosin on actin filaments are masked by

  1. Troponin

  2. Light meromyosin

  3. Heavy meromyosin

  4. Calcium ions
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Skeletal muscle fiber is made up of two types of filaments. They are thick filament (myosin) and thin filament (actin). Contraction of a muscle fiber takes place by the sliding of the thin filaments over the thick filaments.
  • Myosin (thick) filament is also a polymerized protein. Many monomeric proteins called meromyosins constitute one thick filament. 
  • Each actin (thin) filament is made of two ‘F’ (filamentous) actins helically wound to each other. Each ‘F’ actin is a polymer of monomeric ‘G’ (Globular) actins. Two filaments of another protein, tropomyosin also run close to the ‘F’ actins throughout its length
  •  In the resting state a subunit of troponin masks the active binding sites for myosin on the actin filaments.
  • So, the correct answer is 'Troponin'.
Multiple choice zoology locomotion and movement contractile protein structure of muscle muscles and their structure

Thick filaments in muscles are polymerised proteins of

  1. Meromyosin

  2. Actin

  3. Troponin

  4. Tropomyosin

  5. Keratin
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Myofibrils are composed of two types of filaments i.e thin filament (actin) and thick filament (myosin).
  • Actin filaments are thinner as compared to the myosin filaments, hence are commonly called thin and thick filaments respectively
  • Each myosin (thick) filament is a polymerized protein. Many monomeric proteins called meromyosins constitute one thick filament (Myosin).
  • Hence thick filaments in muscles are polymerized proteins of meromyosin.
  • So, the correct answer is 'Meromyosin'.
Multiple choice zoology locomotion and movement contractile protein structure of muscle muscles and their structure

 The thin filaments of myofibril contain  __(A)_ actin and two filaments of (B) protein along with  (C)_  protein for masking binding site for myosin. 

  1. A - 1F B - troponin C - Tropomyosin

  2. A - 1F B - tropomyosin C - troponin

  3. A - 2F B - troponin C - tropomyosin

  4. A - 2F B - tropomyosin C - troponin
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Thin filaments of myofibril contain one filament of actin and two filaments of troponin, along with tropomyosin protein.

So, the correct option is 'A - 1F B - troponin C - Tropomyosin'.

Multiple choice zoology locomotion and movement contractile protein structure of muscle muscles and their structure

ATPase activity in muscle fibre lies with

  1. Light meromyosin

  2. Head of heavy meromyosin

  3. Troponin

  4. Short arm of heavy meromyosin
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • The myofibril is composed of two types of filaments. They are thick filament(Myosin) and Thin filament(Actin).
  • Increase in Ca++ level leads to the binding of calcium with a subunit of troponin i.e troponin-C on actin filaments and thereby remove the masking of active sites for myosin. Utilizing the energy from ATP hydrolysis, the myosin head now binds to the exposed active sites on actin to form a cross bridge.
  • Each myosin (thick) filament is also a polymerized protein. Many monomeric proteins called Meromyosins constitute one thick filament. Each meromyosin has the globular head which is an active ATPase enzyme and has binding sites for ATP and active sites for actin. Hence ATPase activity in muscle fibre lies with Head of heavy meromyosin.
  • So, the correct answer is 'Head of heavy meromyosin'.
Multiple choice zoology locomotion and movement contractile protein structure of muscle muscles and their structure

Actin binding sites are located on:

  1. troponin

  2. tropomyosin

  3. meromyosin

  4. both (b) and (c)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Actin belongs to the family of globular multifunctional protein that forms microfilaments in muscle fibers. The associated proteins along with actin found in thin filaments are troponin and tropomyosin.however the binding sites are located in meromyosin.

So, the correct option is 'meromyosin'.

Multiple choice zoology locomotion and movement contractile protein structure of muscle muscles and their structure

Which of the following proteins is found in the thick filaments of skeletal muscle?

  1. Actin

  2. Troponin

  3. Myosin

  4. Tropomyosin
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
A skeletal muscle is made up of different types of proteins. The thick filaments are made up of myosin while the thin filament is made up of three proteins actin, troponin, and tropomyosin. So, the correct answer is 'Myosin'.
Multiple choice zoology locomotion and movement contractile protein structure of muscle muscles and their structure

Myoglobin is found in?

  1. Muscles

  2. Blood

  3. Lungs

  4. RBCs
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  • Myoglobin is a protein found in muscles of almost all mammals that binds to both iron and oxygen. 
  • It is also made up of heme and globin protein. 
  • The main function of myoglobin is binding to oxygen and carrying it to different muscle tissues.
  • So, the correct answer is 'Muscles'.

Multiple choice zoology locomotion and movement contractile protein structure of muscle muscles and their structure

Read the following statement (A-D) with regards to muscles.


Choose the correct option.

  1. I-bands are isotropic bands and made by actin filaments

  2. A-bands are anisotropic bands and made by both actin and myosin filaments

  3. In between I-bands thin fibrous M-line is present

  4. In between A-bands, thin fibrous M-line is present
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

I-bands (isotropic) contain only thin actin filaments, which is why they appear lighter under a microscope compared to the A-bands.

Multiple choice zoology locomotion and movement contractile protein structure of muscle muscles and their structure

Select the option where the property describing muscle fibres is not associated with wall of stomach.

  1. Presence of actin and myosin fibrils

  2. Branched, multinucleated appearance

  3. Presence of cell junctions

  4. Involuntary nature
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The layers of stomach wall include serosa, muscularis, submucosa, and mucosa these are involuntary in nature and show the presence of cell junctions also, the muscularis layer shows branched and multinucleated appearance.

However, the presence of actin and myosin fibrils is seen in smooth muscles.
So, the correct answer is 'Presence of actin and myosin fibrils'.

Multiple choice zoology locomotion and movement contractile protein structure of muscle muscles and their structure

Which fibres, contractile in nature are found in muscles?

  1. White fibres

  2. Myofibrils

  3. Micro fibrils

  4. Elastic fibres
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Contractile fibres are those fibres which are capable in contraction of the muscles.

 Fibres Nature 
 White fibres (form of mature connective tissue)  Ineslastic
 Myofibrils (skeletal muscle)  Contractile
 Micro fibrils (surface of primary cell wall)  elastic
 Elastic fibres (bundle of connective tissue)  elastic

So, the correct  option is 'Myofibrils'

Multiple choice zoology locomotion and movement contractile protein structure of muscle muscles and their structure

Which of the following are the regulatory protein in the  muscle contraction?

  1. Troponin and tropomyosin

  2. Troponin and actin

  3. Myosin and tropomyosin

  4. Actin and tropomyosin
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Actin and myosin are the contractile proteins, and they interact with each other, causing contraction, while troponin and tropomyosin are regulatory proteins that regulate the interaction between actin and myosin. 
  • Myofilaments(actin and myosin) are packed in functional units of striated muscle referred to as sarcomeres. 
  • Hence, Troponin and tropomyosin are the regulatory protein in muscle contraction.
  • So, the correct answer is 'Troponin and tropomyosin'.
Multiple choice zoology locomotion and movement contractile protein structure of muscle muscles and their structure

In the sarcoplasmic reticulum of resting muscle, Ca$^{2+} $ are held together by which protein?

  1. Nebulin

  2. Desmin

  3. Calsequestrin

  4. Calmodulin
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In the sarcoplasmic reticulum of resting muscle, Ca2+ are held together by calmodulin. Calmodulin is also called as calcium-modulated protein, is a calcium-binding protein present in the cytoplasm. It is present in all eukaryotic cells.it's the function is to bind calcium ions in resting muscle. when the motor impulse is generated and reached to neuromuscular junctions calcium is released from calmodulin which facilitates muscle contraction.

So, the correct answer is 'Calmodulin'.